Paperboard container with locking flaps

ABSTRACT

A container blank is provided which forms a container having a pair of end wall panels defining access apertures therein and a pair of side wall panels. The container blank also includes a plurality of minor flaps adjacent to the end wall panels where at least one of the minor flaps includes a horizontal fold line across the midsection of the minor flap and at least one vertical fold line that runs generally perpendicular to the horizontal fold line and defines at least one folding tab member on one of the minor flap locking tabs. Further, the container blank also has a plurality of major flaps adjacent to the side wall panels, where at least one of the major flaps has a receiving slot for engagement with an associated locking tab. The resulting container provides strength for use in storage including food product storage.

FIELD OF THE INVENTION

The present invention is directed generally to a container constructed from a paperboard blank. More particularly, aspects of the present invention relate to a paperboard container that has increased strength for material handling.

BACKGROUND OF THE INVENTION

In the shipping and packaging industry, laminated containers are used for transporting dry materials and products. In general, laminated containers are constructed from corrugated fiberboard having adhesively bonded layers. These laminated containers are generally constructed initially from a paperboard blank. One type of laminated container is a field pack produce container. This type of produce container has short wall panels connected to short top flaps with slot openings for closing the container. An access hole is generally located in the upper portion of each end of the short wall panels to allow a person to grasp the container to easily move and transport the container and to allow a hose or other device to be inserted into the access hole to fill the interior of the produce container with ice. With these types of produce containers, insertion of a hand or the hose end into the access hole can cause the paper material of the container to tear at the access hole and continue into the slot in the short flap. Thus, over time the container of this construction can become difficult to use and become unlocked. Also, the structural integrity of the container can be significantly reduced.

A need exists for containers that can be handled, moved and filled with product without tearing under normal use. Further, a need exists for paperboard containers that have increased strength for stacking. Specifically, a need exists for containers that limit or prevent damage to its contents when other containers are stacked on top of it.

SUMMARY OF THE INVENTION

The present invention pertains to a paperboard container with increased strength for material handling operations and improved locking function.

In an aspect, there is provided a locking container that is resistant to tearing forces applied thereupon. Flaps which extend from endwalls and sidewalls of the container may be connected to compose a container top. Locking tabs located on minor flaps adjacent to endwalls at a fold line, engage receiving slots located at major flaps adjacent to sidewalls across a fold line. In another aspect, access holes are provided on the endwalls to facilitate movement of the container and for other purposes.

In yet another aspect, the invention provides a container with locking mechanisms that lift the top of the container so as to provide improved protection for contents of the container against damage. When multiple containers are stacked vertically, folding tab elements may be used to connect the top flaps of the container and protect the contents inside of the container.

In another aspect of the invention, a container may include support structures for protecting the contents of the container when stacked with other containers. A support structure may be formed by a fold line construction on a flap with locking tabs that are manipulated into receiving slots of flaps. Containers possessing these support structures may be stacked vertically to reduce the risk that the contents of lower containers may be damaged or crushed by the weight of containers located above the lower containers.

The above and other aspects, features and advantages of the present invention will be readily apparent and fully understood from the following detailed description of preferred embodiments, taken in connection with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a container blank according to one or more aspects of the present invention.

FIG. 2A is a perspective view of a partially closed container erected from the blank illustrated in FIG. 1.

FIG. 2B is a perspective view of another partially closed container erected from a blank similar to the one illustrated in FIG. 1.

FIG. 3 is another perspective view of the container of FIG. 2A erected from the blank illustrated in FIG. 1.

FIG. 4A is a side view of the container illustrated in FIG. 3.

FIG. 4B is a side view of the container illustrated in FIG. 2B where the container is fully closed.

FIG. 5 is an end view of the container illustrated in FIG. 3.

FIG. 6 is a top view of the container of FIG. 3 constructed from the blank illustrated in FIG. 1.

FIG. 7 is a bottom view of a container constructed from the blank illustrated in FIG. 1.

FIG. 8 is a top view of a container similar to that shown in FIG. 3 but with an alternative locking arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a preferred construction of a knocked-down-flat (“KDF”) container blank 100. The blank 100 is used to construct a rectangular shaped container, although other configurations are possible, such as a cube shape. In a general construction, blank 100 includes two side wall panels 106 and two end wall panels 107 connected to four top flaps and four bottom flaps, the boundaries of which are formed by vertical fold lines 77 and horizontal fold lines 120, 140. For reference purposes, the fold lines are depicted as broken lines in FIG. 1. As used herein, a fold line may be a thin band of a weaken region of material. The thin band can be a specific area on a blank formed by conventional manufacturing methods in the paperboard art. Nevertheless, the fold line may be simply a predetermined area for folding along a part of the blank without a weaken area. The KDF container may be constructed by securing together the edges of a blank including the aforementioned panels.

With continued reference to FIG. 1, the top flaps and bottom flaps are provided to form major flaps and minor flaps generally for a rectangular shaped container. Specifically, the major flaps extend from the side wall panels 106 and the minor flaps extend from the end wall panels 107 of the blank 100. The major flaps and the minor flaps may be used in shaping either the container top or bottom portions of a fully constructed container. For ease of explanation, the terms “major” and “minor” are used herein for designating a relative lateral length dimension. In essence, a major flap has a longer length than a minor flap. The major flaps and the minor flaps may contain features to facilitate construction of the container, to provide strength, support and rigidity to the container. The perimeter shape of the flaps allows for interlocking engagement. Further, the shape of the flaps provides a top covering or a floor base for the contents within the container.

In a preferred construction, the blank 100 includes two sets of opposing minor flaps on the end wall panels 107. This minor flap arrangement defines top minor flaps 108 and bottom minor flaps 109 both having locking protrusions. Top minor flaps 108 have the same general perimeter shape including a moveable locking tab 150. Locking tab 151 is disposed on bottom minor flap 109 and may be formed as a fixed tab. Both top minor flaps 108 and bottom minor flaps 109 have horizontal or longitudinal fold lines 110 spanning a midsection portion. The top minor flaps 108 include transverse fold lines 111 which are generally perpendicular to longitudinal fold line 110 and are disposed laterally to the right and left ends of the top minor flaps 108. This configuration of the transverse fold lines 111 defines folding tabs 112 as part of locking tabs 150. The folding tabs 112 pivot about the respective transverse fold line 111.

With continued reference to FIG. 1, a preferred construction of blank 100 includes two sets of opposing major flaps disposed on the side wall panels 106 which define top major flaps 113 and bottom major flaps 114. The top major flaps 113 and bottom major flaps 114 contain die cut receiving slots 115, 117, respectively. These slots 115, 117 are configured to matingly engage in a reliable locking type connection with the locking tabs 150, 151 of the corresponding top minor flaps 108 and bottom minor flaps 109. The connection between the locking tabs and receiving slots withstands forces from handling operations, such as container filling, loading, movement and stacking. The connection between the locking tabs and slots may be purposely disabled under user operation without destroying the integrity of the container.

In a preferred construction, the receiving slot 115 of the top major flap 113 includes a biasing tab 180 which pivots upon fold line 181. In operational engagement with locking tab 150, biasing tab 180 provides a biasing force against the locking tab 150 and surface of the top major flap 113. In particular, the biasing force may be upwardly directed for improved locking performance with locking tab 150. The geometric shape and size characteristics of the receiving slots 117 vary with respect to the characteristics of the locking tabs 151 on the bottom minor flaps 109. Specifically, the receiving slots 117 disposed on the bottom major flaps 114 may be characterized as having a narrower slot width than the slots 115 disposed on the top major flaps 113.

End wall panels 107 may include material handling or access hole feature, such as a die cut aperture 170. In a preferred construction, the die cut apertures 170 are disposed on the end wall panels 107 near the location of a horizontal fold line 120 shown in FIG. 1. Horizontal fold line 120 defines a boundary between the top major flaps 113 and side wall panels 106, and top minor flaps 108 and end wall panels 107 of container blank 100.

The location of die cut aperture 170 on end wall panels 107 provides improved resistance or near elimination of tearing of the paperboard material under normal use conditions. The synergistic arrangement of the end wall panels 107 and die cut aperture 170 in combination with locking tabs 150 advantageously provides improved structural integrity. This is due in-part in that the top minor flaps 108 do not possess slots which can weaken the structural integrity of a panel when under a shearing force. The improved tear-out resistance is provided by the respective locations of locking tabs 150 of top minor flaps 108 and corresponding receiving slots 115 of top major flaps 113. Specifically, locking tabs 150 are located on the top minor flaps 108 while the corresponding receiving slots 115 are located on the top major flaps 113. In this inventive arrangement, a vertical lifting force may be applied to the die cut aperture 170 to lift the container. This lifting force creates an associated shearing stress which is distributed throughout the top minor flap 108 above die cut aperture 170. Advantageously, improved strength is provided when die cut aperture 170 is used in a handling operation to move a formed container and its associated contents.

Die cut aperture 170 allows access to the contents of the container and may be used for inserting ice or slurry. With continued reference to FIG. 1, an access hole 178 may also be used for filling the erected container with a coolant such as ice slurry, or may further be used for material handling. In the mode of material handling, the access hole 178 may serve as a grip feature for lifting the erected container. Further, when multiple containers are located tightly together for storage or transportation, an elongated strap may be run into one access hole 178 and out the access hole 178 on the opposite face to hold the containers either to a palette or to other containers, allowing for tighter and more secure transportation or storage of the containers.

With reference to FIG. 1, in a preferred construction, blank 100 includes stacking tabs 125 that extend from side wall panels 106 and top horizontal fold line 120. Stacking tab receiving slots 130 are generally positioned along the bottom edge of side wall panels 106 abutting bottom horizontal fold line 140 defining the boundary between side wall panels 106 and the bottom major flaps 103. When a container is erected, the engagement of the stacking tabs 125 in the receiving slot 130 assist in stabilizing a columnar stack of containers. It should be recognized that the length of stacking tabs 125 can be varied according to the intended use of the container and desired stabilization performance.

FIG. 2A illustrates a partially closed erected container 200 from blank 100 illustrated in FIG. 1. The container top surface 201 may be formed by securing top minor flaps 108 to top major flaps 113. Specifically, locking tab 150 may be folded along both horizontal fold line 110 and longitudinal fold line 111 to form folding tab 112 on each end of the top minor flap as a result of a pivoting action along the transverse fold line 111. Folding tab 112 may be pivoted along the transverse fold line 111 so that it lies generally underneath the remainder of the top minor flap 108. Subsequently, the two locking tabs 150 on each end of each top minor flap may be inserted into the corresponding receiving slots 115 located on one end of each of the top major flaps 113.

FIG. 3 illustrates a perspective view of container 200 erected from blank 100 that has been fully closed. Container 200 includes minor flaps 108 with the locking tab 150 and folding tab 112. Side wall panels 106 have top major flap 113 which includes a receiving slot 115. As shown in this figure, the locking tab 150 and the folding tabs 112 of top minor flaps 108 and receiving slots 1 15 of top major flaps 113 have been engaged to fully close container 200. In operation, the locking tabs 150 extend into and are configured to engage the receiving slots. In addition, the folding tabs 112 extend toward the receiving slots 115 and engage the biasing tabs 180. In this way, the biasing tabs 180 exerts a resistive force on the folding tab 112 to bias the locking tab 150 into engagement with the receiving slots 115 so the locking tabs 150 are held in engagement with the top major flaps 113 to create a reliable locking connection.

The connection between the folding tabs 112 and the receiving slots 115 connect the flaps 108 and 113 so as to form a container top 201 that serves to enclose products within the container 200. In a further aspect, the top minor flaps 108 are folded in such a way that it is not contiguous with the top major flaps 113 but instead creates a raised support structure 260 with horizontal fold line 110 serving as the apex of the raised support structure 260. This apex allows another container 200 to be stacked on top of the subject container 200 without crushing the contents of the subject container 200.

As illustrated in the side view diagram of a container 200 of FIG. 4A, folding tabs 112 help to hold support structure 260 against the weight of other containers 200 stacked on top of it. The two raised support structures 260 are formed from top minor flaps 108 by folding along the respective fold lines 110 and locking folding tabs 112 of top minor flaps 108 into their corresponding receiving slots 115. In the locked position, the raised support structures 260 formed by the top minor flaps 108 may contact the bottom surface 203 of a supported container.

FIG. 7 illustrates a bottom view of container 200, depicting the interaction of bottom major flaps 114 and bottom minor flaps 109 to form the bottom portion 203. Bottom minor flaps 109 include a horizontal fold line 110 utilized when forming a connection with corresponding bottom major flaps 114 at the receiving slots 117. The receiving slots 117 in the bottom major flaps 114 allow the corresponding locking tab 151 to be inserted therein. The engagement creates a reliable connection that holds bottom minor flaps 109 and bottom major flaps 114 so as to create a bottom or base of the container. Bottom portion 203 provides a lower support to container 200 and encloses the contents in the container to be transported therein.

FIG. 2B illustrates an embodiment of a partially closed container 300 erected from a blank generally similar to the blank illustrated in FIG. 1. Container 300, however, includes locking tabs 150 that possess folding tabs 112 on both the top minor flaps 108 and the bottom minor flaps 109 and receiving slots 115 in both the top major flaps 113 and bottom major flaps 114. In such an embodiment, container 300 will include bottom support structures 362 formed from bottom minor flaps 109 (with locking tab 150) of the container 300 as illustrated in FIG. 4B that is identical to the support structure 260 described above. Container 300 and similar ones may be stacked vertically so that the top raised support structure 260 and bottom support structures 362 of stacked containers can engage each other.

Therefore, containers 200 and 300, possessing either top support structures 260 and/or bottom support structures 362 stacked for storage or transport, protect the contents of the containers during stacking and transportation by leaving the generally more vulnerable top surfaces 201, 301 of the storage area of the container free from a downward gravitational load from other containers stacked above. The integrity of a container and the location, structure, and geometry of the support structures prevent the contents of the container from being crushed or damaged. For example, numerous containers may be filled with food product, such as broccoli, and stacked for temporary storage in a cold storage warehouse. The noted containers reduce the risk that the food product stored in the containers on a lower part of the stack will be crushed or otherwise damaged by the weight of the containers on the upper part of the stack. The weight of the containers may be supported by the frame support structures located at the top end of the end wall panels, rather than bending the top surface of the container which risks damage to the product within the container interior.

Referring to FIG. 4B, bottom support structures 362 of container 300 allow a significant portion of the bottom surface 303 of the container to remain in an elevated state with respect to the floor surface or other support surface. It may be advantageous for certain products, for example produce and other food or perishable items, to be elevated off of the ground to reduce the risk of decay, contamination, or physical damage to the perishable contents. The container also allows air to reach the food contents. Support structures formed on the bottom portion of the container provides support and lifts most of the bottom portion of the container off the floor and prevents damage to the contents.

Containers 200 and 300 facilitate the storage and transportation of contents while also protecting the contents' integrity. Containers 200 and 300 may be used for transporting a large array of products ranging from perishable produce and confectionary items to wholesale products. Many common products, including produce, exhibit a propensity for damage or injury as containers of produce are often stacked tightly to maximize storage or transit ground space. Accordingly, when stacking multiple like containers 200 or 300, stacking tabs 125 may be used to assist in stabilizing the containers stacked in a columnar fashion. In these containers, two stacking tabs 125 extend upward generally along each of the side wall panels 106 of the container. When a second container is placed directly on top of a first container, the four stacking tabs 125 may slidably engage the associated stacking tab receiving slots 130 of another container. Stacking tab receiving slots 130 are generally positioned along the bottom edge of side wall panels 106. The extended vertical height of the stacking tabs 125 can be adjusted to engage the receiving slot 130 and provide for lateral support when multiple containers 300 are stacked together.

As seen from the illustrative end view in FIG. 5, container 200 also contains handle die cut aperture 170 that provides improved tear-out resistance over prior container designs. In a preferred construction, end wall panels 107 may include an access hole 178 which may be used for filling the erected container with a coolant such as ice slurry, or may further be used for material handling.

Containers may be constructed from blanks, such as the one illustrated in FIG. 1, in a variety of steps. The blanks may have slots precut and fold lines demarcated and formed so as to facilitate construction of a container. The container walls and flaps may be formed by folding along the folding lines and locking tabs and stacking tabs may be manipulated as desired. Further, glue strip 199 provides a location for placement of an adhesive to assist the container in maintaining its structural integrity and to provide further support.

A preferred folded configuration of container 200 is illustrated in the top view of a container in FIG. 6. Top minor flaps 108 sit on top of the top major flaps 113 in each of the four corners proximate to the connection between the top major flaps 113 and top minor flaps 108.

FIG. 8 illustrates an alternative locking arrangement of container 200. Container 200 may be folded using a “French Fold” lock resulting in a secure closure of the container. In such a “French Fold” lock arrangement, one end of the container 200 has minor flaps 108 with locking tabs 150 engaging the receiving slots 115 of the major flaps 1 13. The opposing end of the container 200 includes an overlapping arrangement of the minor flap 108 so that it is disposed between both the major flaps 113. In operation, an upward movement of the minor flap is resisted by the major flap 113 disposed on top of the minor flap. In such an arrangement, the container 200 may be locked quickly by using locking tabs at one end of the container and an overlapping flap arrangement at the other end. It should be recognized that the minor flap and the major flaps forming the overlapping arrangement can be provided without locking tabs and receiving slots. Hence, an alternative container can have at least one end of the container with the locking tabs and receiving slot construction and the other end can have to secure locking configuration formed with overlapping flaps.

It is noted that the features of the container blank individually and/or in any combination, may improve locking performance, structural integrity and other benefits of a formed container. While the various features and aspects of the container blank work together to achieve the advantages previously described, it is recognized that individual features and sub-combinations of these features can be used to obtain some of the aforementioned advantages without the necessity to adopt all of these features. For example, a blank may be used to form a paperboard container that can be resistant to tearing forces applied thereupon. Flaps which extend from end wall panels and side wall panels of the container may be connected to compose a container top. Locking tabs located on minor flaps may engage receiving slots located at major flaps. The paperboard container may have an access hole in the end wall panels.

While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described blank, and container and techniques. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims. 

1. A container blank for forming a paper container comprising: a first end wall panel having a top, a bottom, a left side and a right side, the first end wall panel defining a first access aperture therein adjacent to the top; a first side wall panel having a top, a bottom, a left side and a right side, wherein the first side panel is connected along its left side to the right side of the first end wall panel; a second end wall panel having a top, a bottom, a left side and a right side, wherein the second end panel is connected along its left side to the right side of the first side wall panel and the second end wall panel defines a second access aperture therein adjacent to the top; a second side panel having a top, a bottom, a left side and a right side, wherein the second side wall panel is connected along its left side to the right side of the second end wall panel; a pair of top minor flaps connected to the tops of the first end wall panel and the second end wall panel, wherein each of the top minor flaps includes at least one top locking tab thereon, a generally horizontal fold line, and at least one fold line disposed generally perpendicular to the horizontal fold line so as to define a movable tab member adjacent to the top locking tabs; a pair of major top flaps connected to the tops of the first side wall panel and the second side wall panel, wherein the major top flaps include receiving slots that engage the top locking tabs of the minor top flaps; a pair of bottom minor flaps connected to the bottoms of the first end wall panel and the second end wall panel, wherein the bottom minor flaps include bottom locking tabs thereon; and a pair of major bottom flaps connected to the bottoms of the first side wall panel and the second side wall panel, wherein the major bottom flaps include receiving slots that engage the bottom locking tabs of the minor bottom flaps.
 2. The container blank according to claim 1, wherein each of the receiving slots of the major top flaps is defined by a perimeter having a cut line extending around a major portion of the perimeter and a fold line extending around a minor portion of the perimeter.
 3. The container blank of claim 1, wherein the bottom minor flaps include a generally horizontal fold line.
 4. The container blank of claim 1, further including at least one stacking tab formed therein adjacent to the top thereof.
 5. The container blank of claim 4, further including at least one stacking tab receiving slot formed therein adjacent to the bottom thereof.
 6. The container blank of claim 1, further comprising a third access aperture formed adjacent to the intersection of the bottom of the first or second end wall panel and the top of the first or second bottom minor flaps.
 7. A paperboard container comprising: a pair of end wall panels having a top and a bottom each defining access apertures therein adjacent to the top; a pair of side wall panels disposed between the pair of end wall panels having a top and a bottom; a pair of top minor flaps connected to the tops of the end wall panels, wherein each of the top minor flaps includes at least one top locking tab thereon, a generally horizontal fold line, and at least one fold line disposed generally perpendicular to the horizontal fold line so as to define a movable tab member adjacent to the top locking tabs; a pair of major top flaps connected to the tops of the pair of side wall panels, wherein the major top flaps include receiving slots that engage the top locking tabs of the minor top flaps; a pair of bottom minor flaps connected to the bottoms of the pair of end wall panels, wherein the bottom minor flaps include bottom locking tabs thereon; and a pair of major bottom flaps connected to the bottoms of the pair of side wall panels, wherein the major bottom flaps include receiving slots that engage the bottom locking tabs of the minor bottom flaps.
 8. The paperboard container according to claim 7, further comprising a biasing tab adjacent to each of the receiving slots of the major top flaps that engage the top locking tabs.
 9. The paperboard container according to claim 7, wherein the top minor flaps define an upstanding support structure with an apex along the horizontal fold line.
 10. The paperboard container of claim 7 further including at least one stacking tab extending from the top of the side wall panels.
 11. The paperboard container of claim 10, wherein the side wall panels further define at least one stacking tab receiving slot formed adjacent to the bottom thereof.
 12. The paperboard container of claim 7, further comprising a second access aperture formed adjacent to the intersection between the bottom of the end wall panels and the top of the bottom minor flaps.
 13. The paperboard container of claim 7 wherein the pair of major bottom flaps include a generally horizontal fold line and define an upstanding support structure with an apex along the horizontal fold line. 